There are numerous quality control tests for yarns. One such test is for the yarn general appearance. This test is accomplished by winding the yarn onto a rectangular or trapezoidal-shaped black board to allow the side-by-side comparison of half of the yarn sample as a number of relatively short lengths of yarn. This test has been standardized as ASTM D2255-64. The method describes winding the yarn on a rectangular or tapered board. The board covered with the wound yarn is then examined and a visual appraisal of appearance is made that takes into account slubs, hairiness, thick and thin places, broken ends, filaments and other novelty effects. Boards of standard yarns of known commercial quality may be wound and photographed for use as standards. Quantitative estimates of regularity may be made by counting the number of faulty places and expressing these as a percentage of the number of turns of yarn on the board.
This method has been used successfully for years for grading yarns. However, the method is relatively slow, inaccurate, labor intensive, and highly judgmental and thus expensive. The process requires an operator to wind the yarn on the board before the comparison can be made, and it also requires the assessment of a number (generally 5) of independent inspectors. Further, only half of the yarn can be viewed, which decreases the likelihood of faults being detected.